Hypertension
Hypertension is essentially due to a progressive narrowing of the caliber of vessels caused by excessive vasoconstriction, atherosclerotic plaques may further exacerbate the oxygen edeficit in tissues with possible ischemia. H2S doubtless contributes to blood pressure regulation. In experimental models, a deficiency of H2S-producing enzymes results in hypertension whereas administration of H2S donors lowers blood pressure and protects against organ damage. The effect is mediated by interactions with nitric oxide.
In a double blind, placebo controlled clinical trial the daily administration of taurine (inducer of H2S) was effective in significantly decrease blood pressure in pre-hypertensive patients and the effect correlated with an increase in circulating H2S. Thereafter, being cysteine the substrate for H2S synthesis, it was proposed to associate a cysteine donor to further increase the effect, but no associations products were available in the market so far.

References
Van Goor H et al. Hydrogen sulfide in hypertension. https://pubmed.ncbi.nlm.nih.gov/26808704/
Hsu C-N & Tain Y-L. Hydrogen Sulfide in Hypertension and Kidney Disease of Developmental Origins. Int J Mol Sci. 2018 May; 19(5): 1438. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5983690/
Szijártó IA et al. Cystathionine γ-Lyase–Produced Hydrogen Sulfide Controls Endothelial NO Bioavailability and Blood Pressure. Hypertension 2018 Jun;71(6):1210-1217. https://www.ahajournals.org/doi/10.1161/HYPERTENSIONAHA.117.10562?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed
Sun Q et al. Taurine Supplementation Lowers Blood Pressure and Improves Vascular Function in Prehypertension Randomized, Double-Blind, Placebo-Controlled Study. Hypertension 2016 Mar;67(3):541-9. https://www.ahajournals.org/doi/10.1161/HYPERTENSIONAHA.115.06624?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed
DiNicolantonio JJ et al. Boosting endogenous production of vasoprotective hydrogen sulfide via supplementation with taurine and N-acetylcysteine: a novel way to promote cardiovascular health. Open Heart 2017 May 22;4(1):e000600. https://openheart.bmj.com/content/4/1/e000600.long